Washington, Mar 28 (IANS): Top US Democrats have urged Republican chairman of the House Intelligence Committee Devin Nunes to recuse himself from a probe into alleged links between the President Donald Trump's associates and Russia, the media reported.

"The Chair of the House Intelligence has a serious responsibility to the Congress and to the country," House Democratic Leader Nancy Pelosi told CNN on Monday evening.

"Chairman Nunes' discredited behaviour has tarnished that office. (House) Speaker (Paul) Ryan must insist that Chairman Nunes at least recuse himself from the Trump-Russia investigation immediately. That leadership is long overdue."

Pelosi's request followed Democrat Representative Adam Schiff's call for Nunes' recusal.

"We've reached the point, after the events of this week, where it would be very difficult to maintain the credibility of the investigation if the chairman did not recuse himself from matters involving either the Trump campaign or the Trump transition team of which he was a member," Schiff told CNN earlier on Monday.

"The questions are profound enough that I think we need to move past it, and ideally that would mean the chairman ought to recuse himself, not only from the investigation involving potential coordination or collusion between the Trump campaign and the Russians, but also any oversight of minimisation issues affecting the Trump transition since he was a member of that Trump transition team."

Pelosi and Schiff's requests followed a meeting of the Democrats on the House Intelligence Committee, a panel typically seen as more above the political fray than other committees in the House.

Ryan still supports Nunes, spokeswoman AshLee Strong said Monday, and will not ask him to recuse himself.

"Speaker Ryan has full confidence that Chairman Nunes is conducting a thorough, fair, and credible investigation," Strong said.

Nunes himself declined comment when CNN asked him if he would recuse himself from the investigation.